When I call project management a profession, I’m simply using one of the vernacular definitions: “a principal calling, vocation, or employment..” I don’t believe it qualifies for stricter definitions like: “a calling requiring specialized knowledge and often long and intensive academic preparation.”
IMHO, I doubt PM will become a profession in the sense of such legally-sanctioned monopolies like the legal or medical fields. In other words, I think it unlikely that all PMs will need legal sanction for their education, certification, and licensing.
Many PM practitioners would like more formal recognition of their calling. And it is true that PM certifications are required before firms can even qualify to bid on, never mind win, many government contracts. Perhaps PM will end up something like the engineering field, where there are explicit certifications and licensing requirements, but only for some roles. I find it hard to believe that we would get more recognition than that.
That said, it was only 100 or so years ago that lawyers only had to “read law”, so perhaps we should never say never about the professionalization of PM.